Personal Statement Draft 1

Au Wei Ming graduated from Singapore Polytechnic with an in diploma in environmental management and water technology. He has a strong passion for structural design and environmental science. He has been involved during the course of study, he had his internship in Public Utility Board and gained an understanding of the environmental problems and its impacts. He realised that by reusing municipal wastes is a sustainable way that plays a vital role in environmental sustainability.

Executive Summary Draft 1

This report was written in response to develop a solution for an engineering problem. In this proposal, the team presents a method to incorporate plastic waste into concrete. Building and Construction Authority has been urging the stakeholders in the construction industry to use waste as a construction material, providing a sustainable construction in the construction industry in Singapore. Therefore, the team is proposing to incorporate 30 – 40% of plastic waste into concrete.

This proposal will detail the effectiveness of incorporating plastic waste into concrete. The team suggests to partially replacing aggregates with shredded plastic waste and discusses its benefits and limitations. Carbon nanotubes can be added in as a supplementary material to meet any specific design requirements.

An evaluation of the benefits and possible limitations to these proposed solutions has also been included in this report.

Letter of Transmittal Draft 1

14 March 2018

Mr. Huge Lim

Building and Construction Authority

52 Jurong Gateway Road #11-01

Singapore 608550

Dear Mr. Lim,

RE: Proposal for Incorporating Plastic Waste into Concrete

Enclosed for your kind consideration is the following proposal for a new method of creating concrete in Singapore. This proposal has been prepared in response to your letter of authorization for the report.

The report consists of a description of the current situation regarding plastic waste, the rationale behind the proposed solutions, an evaluation of the benefits, suggested alternative solutions and a detailed summary of all related primary and secondary research. We target to reduce the plastic waste in Singapore and we have provided information on the methods to integrate plastic waste into concrete, and an analysis on how plastic waste behaves in concrete.

We would like to express our gratitude to you for taking the time to read this proposal. Your consideration of our suggestions in the integration plastic waste into concrete is greatly appreciated. If you have any question regarding the information of the report, feel free to contact us and we look forward to working with you.

Sincerely,

Serena Koay

On behalf of Team H.S.M       

Reader's Response Final

In the article “Duo Turned Plastic Waste into a Concrete Idea,” Goy (2016) explains that the company BlueRen discovered a method of integrating carbon nanotubes from converted plastic waste into cement through a sustainable approach. The article quotes co-founder Aravind Muthiah, who explains that their “technology is about upcycling, and converts plastic waste into high-value products.” The process turns plastics into hydrocarbon gases, creating the carbon nanotubes. Carbon nanotubes are beneficial due to their characteristics that can aid in the reduction of cement by 30% in concrete. Despite the multiple benefits, usage is constrained as the nanotubes are expensive and release harmful gases. To combat these issues, BlueRen developed a recycling process using an alternative mineral as a catalyst that is less harmful to the environment. BlueRen plans to expand on its prototype and to commercialize its technology. While the author mentioned the multiple benefits of carbon nanotubes, there are still significant environmental impacts from plastic recycling that the author did not discuss in detail.

One example of the environmental impact that the author did not mention is the production of volatile organic compound (VOC). According to Soffar (2016), VOC is one is the environmental impacts of melting plastic. Government of Canada stated that VOCs are organic compounds that have high vapour pressures and can evaporate readily into the atmosphere. When VOCs are released into the atmosphere, they are one of the main sources for the formation of ground-level ozone and its particulate matter causes smog. Furthermore, VOCs are also toxic to plants and animals that are near to the pollutant origin. Usage of the recycled plastics containing VOCs poses a serious health risk to users.

The production of plastic resin is another example of environmental impacts from the manufacturing and recycling process. They can seep into food that is stored in the recycled plastic containers. The amount of harmful chemicals that users absorb can increase based on certain factors like temperature, types of plastic and the plastic age. This environmental issue is related to the health issues and it causes damages to the liver, kidneys and central nervous system. 

Another source of environmental impact is the unrecyclable plastic waste found during the recycling process. Hartman (2017) mentioned that recycling centre employees might find unrecyclable plastics and discard them improperly. Unrecyclable plastic includes plastic that consists of food waste or debris. Plastic, in general, are not considered under hazardous waste and recycling it is not mandatory, such waste can be improperly discarded and the plastic waste problem continues. 

Hartman (2017) explained that downcycling is the recycling of plastic into a less valued product than its predecessor. The recycled plastic has limited use as compared to new plastics and other recycled materials. After the plastic has been recycled once, it is usually ineligible for another round of recycling. This would mean that the recycled plastics will eventually end up in the landfill despite having been made into a less useful product. Downcycling is just delaying the inevitable process of plastics ending up in the landfill as the industries constantly demand for new plastic.

In general, BlueRen’s technology is about converting plastic waste into a high-value product and this technology will eliminate downcycling. Although carbon nanotubes can be effective and readily available, the mentioned environmental impacts from plastic recycling should be taken into serious considerations. The continual of recycling plastic will only worsen the impacts that are already present. (567 words)

References:

Bio-tec. (n.d.) Environmental effects of plastic pollution. Goecopure. Retrieved, February 04, 2018 from http://www.goecopure.com/environmental-effects-of-plastic-pollution.aspx

Goy. P. (January 11, 2016). Duo turn plastic waste into a concrete idea. The Straits Times.http://www.straitstimes.com/singapore/duo-turn-plastic-waste-into-a-concrete-idea

Hartman, D. (April 24, 2017). The disadvantages of recycled plastics. Sciencing. Retrieved, February 04, 2018 from https://sciencing.com/disadvantages-recycled-plastics-7254476.html

Richards, H. (August 05, 2014 ). Plastic Recycling: The process, advantages and disadvantages. 33^rd Square. Retrieved (February 04, 2018) from  http://www.33rdsquare.com/2014/08/plastic-recycling-process-advantages.html

Soffar, H. (July 28, 2016). Plastic recycling advantages and disadvantages. Science Online. Retrieved, February 04, 2018 fromhttps://www.online-sciences.com/industries/plastic-recycling-advantages-and-disadvantages/

Volatile organic compounds overview. (June 22, 2017). Government of Canada. Retrieved February 04, 2018 from https://www.canada.ca/en/environment-climate-change/services/managing-pollution/sources-industry/volatile-organic-compounds-consumer-commercial/overview.html

Volatile organic compounds (VOCs). (August 23, 2017). U.S. National Library of Medicine. Retrieved, February 04, 2018 from https://toxtown.nlm.nih.gov/text_version/chemicals.php?id=31

Zero Waste Singapore. (December 8, 2008). Plastics recycling. Retrieved, February 04, 2018 from http://www.zerowastesg.com/2008/12/08/plastics-recycling/

Technical Report Draft 1

1. Introduction

1.1 Background

Singapore named the “The Garden City’’ as it is one of the greenest countries in Asia. Thus, Singapore has been emphasizing on waste management as Singapore’s only remaining landfill is Semakau landfill. Semakau landfill is predicted to be filled by the year 2035. Singapore’s population is growing at a staggering rate every year from 4,027.9 million in 2000 to 5,612.3 million in 2017. An increase of 1584.4 million in the past 17 years.The increase in population eventually leads to the incline of solid waste generation. In 2016, there were 7.81 million tonnes of waste being produced as compared to the 7.67 million tonnes in 2015. There is an increase of 140,700 tonnes. Similarly, if this rapid increase in waste generation continues, the landfill would be filled up before the expected year.

National Environment Agency (NEA) conducted several surveys about the different waste type, waste disposed, and waste recycled, waste generated and recycling rates in 2016. Plastic waste is one of the main contributing waste in Singapore as it has one of the highest amount of waste generated and the lowest recycling rate. Examples of plastic waste are takeaway containers, plastics utensils, plates, and cups. In 2016, 822,200 tonnes of plastic waste was being generated, however, only 7% of it was recycled. The remainder is incinerated and then sent to the landfill. The recycling rate of plastic waste cannot keep up with the increase in plastic waste. This causes more and more plastic waste to be sent to the landfill.

In addition, NEA is urging our local construction industry to investigate the usage of recycled and waste materials. Plastic waste can be recycled and be made into other products like carbon nanotubes and different chemical fuel. However, it is not fully utilized due to the difficulties in collecting and sorting plastic waste.

Samwoh Corporation has been carrying out research on repurposing waste materials and incorporating them into concrete. The project team sees the potential of using plastic waste as aggregates in concrete and is going to focus on promoting the possibility of incorporating plastic waste into concrete.

1.2 Problem Statement

Samwoh Corporation should be incorporating 30-40% of plastic waste into concrete as it is environmentally friendly and provides a new purpose for plastic waste. Plastic waste is one of the largest waste contributors and they are not being investigated extensively as a material in green concrete. According to National Environmental Agency (NEA), there were 822,200 tonnes of plastic waste being generated in 2016 and only 7% of them were being recycled resulting in depletion of space in the landfill as our landfill would be filled up by 2035. Looking at the problem, this research team decided that there is a need to incorporate 30-40% of plastic waste into concrete.  This will reduce the amount of plastic waste being sent to landfills and reducing the need for raw materials of conventional concrete.

1.3 Purpose Statement

This report aims to promote the idea of incorporating plastic waste into concrete to Samwoh Corporation which then can be adopted by Singapore’s construction industry. This will reduce the amount of plastic waste needed to be sent to the landfill. The intention is to enhance the understanding of the advantages of plastic waste in concrete.

2. Proposed Solution

Green concrete refers to concrete that has partial or complete replacement of either cement, fine or coarse aggregates with waste or residual products. When the substitution materials are less dense than the conventional materials, lightweight concrete is produced. There are various ways plastic waste can be incorporated into concrete.

Plastic waste can be processed, typically through shredding and low temperature melting. The processed plastic can be used as coarse aggregate replacement in concrete.

Another way of using plastic waste into concrete is to convert plastic waste into carbon nanotubes. Carbon nanotubes are tiny cylinders of carbon atoms. They can be group into two different types of carbon nanotubes which are the single-walled carbon nanotube (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). MWCN is most commonly used as they are cheaper to make and have a better reinforcement in cement concrete. An innovation by technology company called BlueRen believes that more plastic waste can be recycled and the use of cement to make concrete reduced, as carbon can be used as an additive in concrete idea.

The project team is focusing on the process of converting plastic waste into shredded plastic which can be used as a replacement material for coarse aggregates in concrete.

2.1 Benefits

Kumar. P. and Kumar. G (2016) mentioned that in the last 20 years, research on the usage of urban waste in building materials has been increasingly published. Aside from the environmental benefits, the wastes yield positive effects on the properties of the final product. Amidst the municipal solid waste, plastics have received a lot of attention because they are not biodegradable.  Plastic waste has been increasingly used as a partial substitute of aggregates. The usage of plastic waste as aggregates can greatly reduce the weight of the concrete, this is called lightweight concrete.

It is identified that the usage of plastic aggregates can improve the ductility in concrete. Ductility helps the material to stretch under tensile stress, this property very important in the safety of the building. In an event where the building starts to collapse, people in the building still have time to escape as the concrete would deform significantly before reaching failure. Using plastic aggregate is also cost effective and energy efficient. Plastic aggregates can effectively help to maintain the building interior temperature in hot weathers.

According to Sofi. and Jaivignesh. (2016), the incorporation of shredded plastic, properties such as abrasion resistance, impact resistance, ductility, shock absorption, and thermal conductivity can be improved. Apart from the benefits mentioned, Kumar. P. and Kumar. G (2016) also explained that plastics are versatile and it can be customised to meet specific technical requirements. They have a lighter weight than other materials, therefore, reducing the fuel consumption during transportation. Plastics are very durable and can last a very long time. Moreover, they also have great resistance against chemical, water, and impact. Most importantly, they cost less to produce than traditional concrete. This serves as a way to improve the properties of concrete and act as a solution to the disposal of plastic to some extent.

Samwoh can become one of the leading construction companies in Singapore to use lightweight concrete effectively. Lightweight concrete can be used as non-loadbearing concrete such as concrete panels that are used in facades. By using shredded plastics as an aggregate, Samwoh can bring down the cost of producing concrete as aggregates are relatively pricier than plastic wastes. Samwoh can have a centralised plastic waste collection centre to collect plastic waste disposed by their employees and use it in their concrete batch. This provides self-reliance, hence, reducing the cost to purchase and transport plastic waste from contractors. Furthermore, this shows that plastic aggregates can also be used as a plastic disposal method in the company.

Goy (2016) mention that carbon nanotubes have many uses as they are light, strong and can conduct electricity well. While Goy (2016) may have mentioned the physical properties of carbon nanotubes, Suhendro (2004) provides even more physical properties of carbon nanotubes to prove that carbon nanotubes are better to add to concrete. Suhendro (2004) states ‘multi-walled carbon nanotubes (MWCNTs) are usually high strength, ductile, crack-free and durable’.

2.2 Evaluation

There are two main disadvantages when it comes to incorporating plastic into concrete. Firstly, plastics have a low bonding property. Hence, it causes the compressive, tensile and flexural strength of the concrete to reduce. The concrete might not be strong enough to be used as a load-bearing beam, even at the higher part of the building. Even with reinforced steel added, normal concrete would be more suitable to support a higher amount of load.

Secondly, plastic wastes have to be cleaned condition before being added to the concrete mixture as aggregates. Therefore, it is a hassle and an additional cost to ensure that plastics are unsullied. The overall cost would also increase when equipment might be required to monitor the gas emission and the presence of toxic and polluting elements. However, this only applies when there heating is required in the process.

Despite the mentioned disadvantages, incorporating plastic waste as aggregates into concrete are extremely effective has numerous advantages, such as the improvement of properties of concrete at a cost-efficient approach. These concretes need not be loadbearing concrete as its decreased strength might make it suitable for places with heavy loads. They can be placed in the higher part of the building where the higher floor would mean that it would be carrying lesser loads. They can be used concurrently as a lightweight concrete for aesthetic purposes in the building, without drastically increasing the total load. High ductility is one of the most useful properties in this concrete, it is useful in harsh conditions as it will expand and contract well, as well as having freeze-thaw resistance.

Aggregates can be partially replaced by plastic waste as it can effectively improve the properties of the concrete and lessen the total weight of the building. The reduction in compressive, tensile and flexural strength can be overcome by placing the concrete at higher levels. So that it does not have to withstand addition load from other floors. The use of waste plastic aggregate can be effectively used because of its properties enhancing and lightweight benefits

There is one major weakness about carbon nanotubes which is barriers to green concrete  Barriers to green concrete, Due to building industry’s profitability, it depends on how quick the construction schedules. The faster the building is being built, the faster they get their profit.  Thus, they prefer not to use green concrete as green concrete requires a life-cycle cost saving from the conversion of material and energy.

3. Methodology

This project team performed primary and secondary research that includes a site visit and online materials from various sources and government organizations.

3.1 Primary Research

The project team had the opportunity to visit Samwoh Research and Development Centre as one of our module site visit. The project team talked to the lab manager, Mr. Teo Yong Boon regarding incorporation of plastic into concrete and there is researches on lightweight aggregates and adding of carbon fibres into concrete. However, there was no information regarding the recycling of plastic waste for concrete.

3.2 Secondary Research

A range of secondary data was obtained from official websites, news articles and research journals. This project team gathered statistics regarding Singapore’s waste generation and recycling rate from National Environment Agency (NEA)’s website. A news article has been published quoting NEA promoting Singapore’s construction industries to incorporate more recycled and waste materials as building materials were used as a motivation to promote our idea to Samwoh Corporation.

4. Conclusion

Research has shown that our only landfill will be fully filled by the year 2035. This project team seeks to reduce one of the main culprit, plastic waste, through promoting the recycling of plastic waste and using them as a material in concrete to our local construction industry. While processing the plastic waste can be costly, we believe that it would reduce the amount of plastic waste and benefit the country in the long run.

In conclusion, it is crucial that Singapore explores new ways of waste management. We believe that our proposed solution will be one of the stepping stones towards reducing the amount of plastic waste sent to landfill.